Comments explaining why we include a header tend to go bad.  This
one's almost comical: not only doesn't qemu-options.hx use
MAP_POPULATE anymore (since commit ef36fa14, v2.0.0, 2013), even the
include it applies to got moved away in commit 02d0e095 (v2.7.0).

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>